The goal of this project is to develop a family of nitric oxide-releasing materials (NORM), formed by adding nitric oxide (NO) donor compounds to polymers. The enhanced NORM developed in Phase I of this effort released NO for a prolonged period of time, at rates exceeding the release of the normal endothelium. The NO donor formulations from Phase I will be combined with commercially-available biopolymers. The resulting NORM will be used to treat prosthetic vascular grafts, which will be tested in long-term implantation experiments in sheep to evaluate the efficacy of the materials in prolonging patency. The goal of the project is to focus on developing a prosthetic vascular graft with improved long-term patency as a commercial application of NORM. The advances in NORM technology achieved in pursuit of this goal is expected to lead to other applications of this technology. If successful, NORM technology has the potential to contribute substantially to the field of prosthetic vascular grafts. The number of grafts implanted for hemodialysis access alone is a sizeable and growing market. Failure rates with prosthetic grafts are approximately 40% after one year for lower extremity bypass and hemodialysis grafts. Early thrombosis is common, as is long-term failure due to intimal hyperplasia. Nitric oxide released from NORM may potentially contribute to preventing short- and long-term failure modes. A pilot study showed promising results for short-term benefits.